Arguments for evolution

I recently brought up my atheism to a christian friend last night (through email) and explained why I now disbelieve religion. A couple of the reasons included scientific basis for how old our planet actually is, such as carbon dating, dendrochronology, radiation half-life, evolution, and so forth. Some of these methods I know date the world much, much older than the bible's approximation of 6-10,000 years. So of course, she came back with arguments against these methods and evolution.

1. "Carbon dating is not an exact science either."

With this, she mentions that scientists "redate" things because they retest and come up with different answers. Even still, the differentiation is minute in the grand scheme of things correct? From what I've understood about carbon dating is that it's quite accurate (at least relatively).

2. Drum roll please... "Even evolution is a theory."

I hear christians using this all of the time. I even dropped it a few times myself previously. I do know that there are several definitions of the term 'theory,' and the theory of evolution is proven by facts, the same facts that disprove creationism and intelligent design.

What are some good arguments to come back with? I am asking advice mainly for my own education, so I would like some handy unbiased resources and I can form my own answers. One of her arguments as well was "don't you think that the sources you have studied might have been funded by scientists trying to prove their theories?" Implying that any site you go to is biased in one direction or the other.

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The colloquial meaning of theory is "assumption" or "speculation". In science that's called "hypothesis". A scientific theory usually has these qualities:

- testability and falsifiability

- supported by several sources of evidence

- predictive ability

"Scientific fact" also has a different meaning. First, it can mean "observation". So in that sense facts don't prove a theory. Strictly speaking you can't prove scientific theories. Scientific proof is a mathematical concept. Facts are used as evidence for support.

It can also mean a theory for which there is such overwhelming evidence that it is widely accepted. That is the case with evolution

Carbon dating is as exact as realizing that it'll take me roughly sixteen hours from South Carolina to Boston. ~850 miles at ~60 miles per hour, with the occasional break to get food, gas, or coffee, bathroom breaks, and the fact that I'm going to have to deal with NYC and Washington, D.C. (not in that order). How do I know this? Because I know the speed limit on the interstate and what happens around NYC and DC. And because I've driven across the country about half a dozen times. Google estimates it at about 15 hours, but I think that's optimistic (seriously, DC and NYC are hellacious snarls. Except at 3 AM. Then you can get across DC in about 30 minutes instead of 3 hours.

Anyway, carbon dating is as exact as knowing how long it'll take you to drive a certain distance. Only if something really weird happens will you be wrong. Carbon dating compares the relative amounts of two isotopes of carbon, carbon fourteen (6 protons, 8 neutrons) and carbon twelve (6 protons, 6 neutrons). Over time, C-14 decays into nitrogen fourteen (7 protons, 7 neutrons). This process takes time, such that every ~5800 years, half of the C-14 disappears. If you start with a gram, 5800 years later you only have half a gram. Thus you can compare the amount of C-14 and C-12 (which doesn't decay) and know how old something is. It's been made more precise over time as we've learned to take into account annual and decennial fluctuations in the levels of C-14, and centennial, and millenial... C-14 is produced in the upper atmosphere by the sun and that varies cyclically (with many overlapping cycles). These have been calibrated by many things (very old trees, ice cores many thousands of years old, etc). and are accurate to within a a few percent. When you're talking about things many thousands of years old, this is damn good. When you're talking about things just a few thousand years old, it's still really damn good (3000 years plus or minus thirty?). It's accurate, and it works.

Okay, the response to "just a theory" is really easy. Gravity is just a theory. Seriously. Look it up. I wish fundies would shut the hell up about "just a theory".

1) Carbon dating doesn't really age the earth at all since, as Steve mentioned, it can only go back about 60,000 years. But, like you said, Radiometric dating (of earth rocks as well as meteorites), as well as Helioseismology and Surface Exposure dating of moon samples all suggest an age for the earth around 4.55 billion years with about 1% variation. So again, we have a situation where the claim is supported by multiple experiments and evidence with little relative error.

2) I love this. Imagine what they'd say if you countered with, "By your definition, Jesus is just a theory". But that would imply that you agree with their definition of theory, which completely diminishes the strength of Evolution. Best to address this issue as Steve described.

regarding the final argument of hers that you mentioned... Are some scientists biased? Sure. They're human, not perfect. But that's why we have the Scientific method and peer review. You can bet that for every biased scientist, there's at LEAST one competitor studying their work holding them accountable.

Haha, I would get a good laugh out of saying "By your definition, Jesus is just a theory." The sad news is, when I emailed her back, she came back with a one line email, "I hope you find all the answers you're looking for." In my reply, I laid out all of the facts for evolution, a prime example --> the rapid evolution of P. sicula, and some bits about carbon dating and more accurate forms of telling the earth's age. I also made mention of how god doesn't answer prayers, people do. And all I got back was this one single line. I can't even reason with Christians that are my friends. They refuse to be reasoned with. It's sad.

Just ask them what research have they done on the Theories of Evolution? Where did they get their source of information? If they say a religious site then you explain to them that religion doesn't research to find the facts of Evolution, scientist do, try reviewing scientific studies instead of staying in your protective cover and looking towards your fellow religious people to help keep you in your bubble of false facts. Evolution research keeps finding additional answers/facts that just continue to confirm it's a true theory.

Did you ask this person why they didn't bring up the banana also? Sounds like they've been reading or hearing these fairy tales from the religious freaks. If he didn't bring it up, might be that he realizes that our current banana isn't a natural banana but was man-made. If he does know this but heard the BS stories about it, explain to him that Carbon Dating and Theory of Evolution goes right along with the banana story. That it's all made up BS to try to disprove facts in favor of their beliefs.

In the end I just tell them......don't take my word for it, do your own research and don't research on a religious sites for facts about science because you'll find no true answers there. If you can't do that then you don't want to know the truth, that's plain and simple, so keep your blind and dumb faith if you wish. This usually shuts them up real quick!

Well, she argues that the scientific sites would be biased toward evolution or whatever they're trying to prove. I explained the process of peer review and how scientists are held accountable. No answer. Seems that, like I said in a reply just above you, that Christians refuse to be reasoned with. I've been there before, the indoctrination forced upon me as a child kept me blind to the truth. But now is a different story. I'm glad to be free! Thanks for your input!

Hell, I feel for you. Everytime I post something up on Facebook that denounces "intelligent design" or pro-thought/contemplation (thank you Michelle Bachman for providing TONS of fodder) I have some friends that always come back with this same kind of nonsense. I even tried the Jesus theory stuff on him - only to have a rebuke of "Well, Paul wrote about him right after he died..nah nah nah" I dropped it. Some people are content to walk around with blinders and their smug since of spiritual superiority.

I haven't yet professed my atheism, but I do know that whence I do, I will lose a lot of 'friends.' On Facebook I keep in touch with a lot of old christian friends from out of town, and some have already dropped me for no reason. I can only imagine what I will get when I say, 'Hey, I'm atheist.' I might be flogged and stoned, maybe even crucified.